2526 Journal of Applied Microscopy 



drug. If the powder be the product of a bark or a wood, a leaf, a root, or a 

 seed, the elements common to each one of these should have been studied and 

 well understood. Wood fibres, if found to any extent in a powder of a bark, 

 would naturally be regarded with suspicion. Bark elements found in powdered 

 leaves would likewise cause suspicion to rest upon the preparation under consid- 

 eration. But if the adulteration consists of similar elements of the same part of 

 the plant, the problem becomes more difficult. Ver)' close examination of the 

 structure of the elements of the drug under consideration is then absolutely nec- 

 essary. It is not infrequently the case that substances of a similar kind but of 

 inferior and cheaper varieties are used, as in the case of Ceylon cinnamon, which 

 may be adulterated with the inferior variety known as the Saigon cinnamon. 

 Under the microscope we find in the Ceylon cinnamon an absence of cork 

 cells ; the stone cells are more elongated and unevenly thickened than in the 

 other variety. These and other less important characteristics enable one to 

 determine the character of the powder, and to detect admixture. Schneider calls 

 attention to the admixture of Apocynum cannabinum with A. androsaemifolium ; 

 Surinum quassia with Jamaica quassia. These resemble each other as to gross 

 appearances, but the histological characters are quite different. A. androsaemi- 

 folium is distinguished from the other species by the presence of stone cells. 

 The Surinum quassia differs from the other in the form of the medullary rays 

 and the presence of stone cells in the bark. Powdered senega has been adul- 

 terated with soap bark. This latter may be detected by the presence of readily 

 distinguished liber fibers only made manifest by the use of the microscope. 



It is clear that the student in pharmacy should be well drilled in the histo- 

 logical elements of vegetable powders and be made familiar with the use of 

 proper microscopical reagents. The laboratory work should be supplemented 

 by lecture room demonstration. Here we find the lantern to be of great import- 

 ance and utility. A lantern for this purpose should be provided with an easily 

 adjusted microscopical projection as well as a projection for photographic slides. 

 In the preparation of slides for demonstrating the elements in powdered drugs 

 we find considerable difficulty. Powders cannot be prepared by staining and 

 clearing, as thin sections may be, for projection, and so do not give sufficient 

 contrast to bring out details of structure sufficiently. The lantern may show 

 certain characteristics that are helpful, but these are not entirely satisfactory to 

 instructor or student because, in the case of powders, the detailed structure 

 cannot be made out at the distance the student must sit from the screen. The 

 object loses its sharp outline and detail in its projection from the objective to 

 the screen. To overcome this drawings can be made of structures under the 

 camera lucida, and from these lantern slides may be made in the usual way. 

 When these are made and used in the lecture room in connection with the lab- 

 oratory work with the compound microscope the student cannot fail to see the 

 connection and the instructor is decidedly helped in his work. 



As an example of such a lantern slide we have prepared and present here 

 one which illustrates a mixture of powdered senna leaves with powdered savine 

 (Juniperus sabina). These leafy drugs are totally different in their gross char- 

 acteristics, but strange to say, in the powdered state have some characteristics 



